The present invention refers to a device for supplying inhalation gas to and removing exhalation gas from a patient, including a pipe member, suited to be introduced into the trachea of a patient and comprising a first pipe conduit, which is intended for said inhalation gas and has a distal outlet opening arranged to be positioned at the dividing region of the main bronchi of the patient during use of the device.
The introduction of such devices for the supply of inhalation gas and the removal of exhalation gas, so called intubation, is made as a matter of routine in medical treatment of patients which need external breath support from a respirator. The device includes normally a plastic pipe, a so called endotracheal tube, which via the throat is guided down into the trachea to a position at the dividing region of the main bronchi. The endotracheal tube is fixed in the trachea by means of a fixing member which is provided slightly above the distal end of the tube and inflated to airtight abutment against the inner wall of the trachea. Air exchange, i e supply of relatively oxygen-rich inhalation gas and removal of exhalation gas, takes place through one single channel in the tube, which via an external manifold is connected to the supply outlet and removal inlet, respectively, of the respirator.
The body reacts in a natural way against foreign bodies and organisms, which are present in the airways, by an increased excretion of secretion from the mucous membranes in combination with an increased activity of the cilia. The purpose of the cilia is to catch and transport impurities and secretion out of the body by moving in such a way that they transfer an upwardly directed movement to these impurities and secretion.
When the tracheal tube is installed in the trachea, the cilia may not act any longer in the intended manner since the tracheal tube and the fixing member closes the natural transport way for the secretion, i e the natural cleaning system is by-passed. In addition, the tracheal tubes, which are used today, do not have a satisfactory capability of removing the secretion since the same quantity of gas is transported successively in both directions through the channel of the tracheal tube. Due to these two factors, the secretion and phlegm will be collected in the airways beneath the fixing member. In order not to completely close off the airways by phlegm and thereby prevent an efficient gas exchange, the airways has to be sucked continuously, typically in intervals of 2-3 hours night and days, to drain collected phlegm. Such suction drainage is performed by means of a catheter, which is guided down through the tracheal tube and which, by means of a sub-pressure, sucks secretion to a collecting container. However, suction drainage by means of a catheter is a process which is time-consuming and expensive, and frequently involves complications. Some usual such complications are injuries on the mucus membranes, infections by contamination of the lower respiratory tract, coincident alveoli in the lungs, acute oxygen deficit, heart disorder and unprepared extubation. In addition, the patient is subjected to significant stress, discomfort and a sense of suffocation. There are also other grounds frequently involving pneumonia due to the treatment by conventional endotracheal tubes. Since the fixing member is positioned far down in the trachea in order to minimise the exposure to the secretion producing surface of the trachea, secretion containing bacteria will remain above the fixing member. During exhalation it is not unusual with leakage at the fixing member, wherein contaminated secretion is drawn downwardly into the lungs during the subsequent inhalation.
U.S. Pat. No. 4,646,733 discloses an endotracheal tube which is intended to be used during high frequent respiratory treatment. The high frequent tracheal tube, which operates with air pulses in the frequency range 1-50 Hz, may be guided downwardly in a conventional tracheal tube to such a position that air pulses generated are guided into the bronchi. The trachea is in its extension by-passed in a conventional manner.
EP-A-92 618 discloses another type of endotracheal tube having an inner pipe conduit: which ha an expandable fixing member at its distal end, and having an outer pipe conduit, which is shorter than the inner pipe conduit and which also has an expandable fixing member at its distal end. The fixing member of the outer pipe conduit is arranged to fix the outer pipe conduit in the throat while the fixing member of the inner pipe conduit is arranged to fix the inner pipe conduit in the trachea or the gullet. The supply and removal of air always takes place through the same pipe conduit.
The object of the present invention is to overcome the problems mentioned above and provide an improved device for the supply of inhalation gas to and the removal of exhalation gas from a patient. In particular, it is aimed at an in this connection improved removal of secretion from the airways.
This object is obtained by the device initially defined, which in addition includes a second pipe conduit, which is intended for said exhalation gas and has an inlet opening provided above said outlet opening, and a fixing member, which is arranged to be introducable into the trachea and to enable fixing of said pipe conduits in the trachea, wherein the fixing member is arranged to be provided substantially immediately beneath the larynx of the patient and wherein the inlet opening of the second pipe member is provided substantially immediately beneath a fixing member and at a substantial distance from said outlet opening.
By such a device, the second pipe conduit, which removes the exhalation gas, will end just beneath the larynx, which allows the cilia in the trachea to operate substantially normally and thereby transport secretion upwardly towards the inlet opening of the second pipe conduit. The secretion which is excreted may thus, to a substantially higher degree than at conventional endotracheal tubes, be transported away together with the exhalation gases. This transport of secretion is also substantially facilitated by the fact that the device according to the invention includes two separate channels, one for the inhalation gas and one for the exhalation gas, and that the outlet for the inhalation gas has an orifice substantially distally with respect to the inlet for the exhalation gas. Hereby, an airflow in one direction is obtained in the pipe conduit as well as in the trachea, i e a closed flow circuit without so called xe2x80x9cdead spacexe2x80x9d. Also the gas exchange is more effective at the same time as impurities, in case of a possible leakage around the fixing member, are prevented from reaching the lungs by the upwardly directed airflow in the trachea. Furthermore, the fixing member is arranged to be positioned immediately beneath the larynx, which prevents secretion and phlegm from remaining in the trachea above the fixing member.
According to an embodiment of the invention, a distance member is provided around the first pipe conduit between said inlet opening and said outlet opening, and is arranged to ensure that the first pipe conduit is located at a distance from at least one part of an inner wall of the trachea. In such a manner a free passage is ensured for the exhalation gas and in addition the first pipe conduit is prevented from abutting the inner wall of the trachea, where it might have a negative influence on the function of the cilia. Advantageously, the distance member may include at least one resilient element, which is arranged to abut the inner wall of the trachea with an abutment surface which is significantly less than the area of the inner wall of the trachea. By such a resilient or elastic element, it is ensured that the distance member does not injure the inner wall of the trachea. Thanks to the relatively small abutment surface of the distance member, the cilia on the inner wall may be permitted to operate substantially unobstructed. According to an advantageous embodiment said element has a thread-like shape and extends in a helical-like. path. Thereby, the distance member may include several such thread-like elements, e g two, and in such a manner it is ensured that the first pipe conduit is positioned approximately centrally in the trachea. According the another advantageous embodiment, the distance member includes a net-like tubular structure arranged to abut the inner wall of the trachea.
According to a further embodiment of the invention, the first pipe conduit extends in the second pipe conduit. In such manner it is possible to preheat the normally colder inhalation gas by means of the warmer exhalation gas in an efficient manner. Thereby, the second pipe conduit may include at least two pipe portions, sector-shaped in cross section, which extend substantially in parallel to each other and are separated by means of a wall member. Furthermore, the fixing member may include an expansion body, which is arranged to be expandable to sealing abutment against the inner wall of the trachea by the supply of a medium. By such a fixing member, the pipe member may be fixed in a desired position immediately beneath the larynx, and in addition a substantially tight abutment against the inner wall of the trachea may be obtained.
According to a further embodiment of the invention, the second pipe conduit includes a collecting member, which is arranged at a distance from said inlet opening to be located outside the patient and which is arranged to collect liquid and particles from the exhalation gas. By such a collecting member it is possible to make the device closed i e the collected secretion does not need to come into contact with the environment and may be removed from the patient.
According to a further embodiment of the invention, a disinfectant is provided in the collecting member and arranged to be distributed successively in the collected liquid. Said disinfectant may advantageously be provided in a number of separate areas along a path, which extends from a lower region of the collecting member to an upper region thereof, wherein said disinfectant is arranged to be released concurrently with the rise of the level of the collected liquid in the collecting member.
According to a further embodiment of the invention, the collecting member includes a level indicator, which is arranged to indicate the liquid collected from the exhalation gas. In such a way, the personnel taking care of the patient may know if the collecting member is full and needs to be replaced. The level indicator may be, designed in different ways, e g it may include a medium which releases a colouring matter when it comes into contact with liquid.
According to a further embodiment of the invention, the second pipe conduit extends into the collecting member and includes an orifice in the collecting member, through which the liquid present in the exhalation gas may exit. Thereby, said orifice may be formed by a pipe portion of the second pipe conduit, which portion is designed to form an audible sound due to bubble formation during said removal when the level of the collected liquid reaches the pipe portion. Such a sound may also function as a level indicator, which facilitates the operation of the device. A well audible sound may be obtained if the pipe portion includes at least one slit, which extends from said orifice, and/or a perforation.
According to a further embodiment of the invention, the pipe member includes a first portion, which extends between said openings and the collecting member, and a second portion, which extends from the collecting member and is connectable to a respirator, wherein said first portion and second portions are releasably connected to the collecting member by means of at least one connecting member. In such a way replacement of the collecting member is facilitated. It is important that such a replacement may be performed quickly since the patient is not connected to the respirator when the collecting member is not connected.
According to a further embodiment of the invention, the pipe member is manufactured in a first material and includes at least one longitudinal portion, preferably two or several portions of a second material, wherein the second material has a higher shape permanence and a lower melting point than the first material. Advantageously, the portions of the second material are formed by strings moulded into the first material or one or several of the wall members. By such a structure of the pipe member, this may in a simple way be given the desired shape by being heated to a temperature in the proximity of the melting temperature of the second material and bent to the desired shape. Thereby, the pipe member may advantageously have a S-like extension above the fixing member.